Electric switch.



No. 669,536. Patented Mar. I2, lam.

T. e. MEINEMA.

' ELECTRIC SWITCH.

Application filed. Mar- 1, 1800.:

(No Model.)

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UNITED STATES PATENT OrricE.

THOMAS G. MEINEMA, OF MORTON PARK, ILLINOIS, ASSIGNOR TO EDWARD \V.HAMMER, OF CHICAGO, ILLINOIS.

ELEGTRBG SWITCH.

SPECIFICATION forming part of Letters Patent No. 669,536, dated March12, 1901.

Application filed March 1, 1900. Serial No. 6,898. kilo model.)

To all whom it may concern:

Be it known that I, THOMAS G. MEINEMA, a citizen of the United States,residing at Morton Park, in the county of Cool; and State of Illinois,have invented a certain new and useful Improvement in Electric Switches,of which the following is a specification.

My invention relates to electric switches particularly adapted formotors, and has for its object to provide a new and improved switch, ofwhich the following is a description, reference being had to theaccompanying drawings, wherein Figure 1 is a diagrammatic Viewillustrating a device embodying my invention. Fig. 2 is a side elevationof the device illustrated in Fig. 1.

Like letters refer to like parts throughout both figures.

As illustrated in the drawings,l have shown my invention as applied toan electric switch for motors. For the purposes of illustration I haveshown diagrammatically a simple switch mechanism for regulating electricmotors, but it is of course evident that any other suitable switch thanthat herein shown may be used, and I in no manner limit myself to theform, construction, or arrangement of switch mechanism.

Referring now to Fig. l, I have shown a switch-arm A, adapted to bemoved past the contacts B, with which are associated the severalresistance-coils 0, adapted to be inserted into the circuit of the motorwhile starting and controlling the same. The switch-arm A is adapted tobe moved in either direction along said contacts, so as to vary theresistance in the armature-circuit in the usual way. The arm A and theseveral contacts are connected in circuit in any suitable manner. Asuitable retracting device is associated with the arm A and is adaptedto move it back to its initial position on the point B when said arm isreleased. It is of course evident that any suitable device for thispurpose may be used, and in the drawings I have illustrated suchretracting device as consisting of the coiled spring A, associated withthe arm, so as to retract it in the manner desired. Associated with thearm A is a magnet D, preferably connected in circuit with the fieldlmagnet coils E of the motor. This magnet is provided with an armature D,movably mounted in proximity to the pole-pieces of the magnet. Connectedwith this armature D is an engaging piece D adapted to engage the arm Aor some part associated therewith and hold said arm in certainpredetermined positions. The parts are so constructed that when thecurrent ceases to flow through the fieldmagnet, and hence through themagnet D, the engaging piece D becomes disengaged from the arm A, andsaid arm is automatically retracted to its initial position. It is ofcourse evident that the engaging piece D may be associated with the armA in any desired manner. As illustrated in the drawings, however, I haveshown the arm A as provided with a series of notches A adapted to beengaged by the engaging piece I). These notches are so positioned thatthe arm A may be held on any of the contacts B between its initial pointB and its closed position B The engaging piece D is preferably eithermade of resilient material or so connected with the armature D that itmay move along the notches A associated with the arm A, while thearmature D is held stationary, thus allowing the proper movement of theswitch-arm A without moving the armature D from intimate contact withthe metal of the pole-pieces of the magnet D. As illustrated in Fig. 1,the armature D is pivoted at the point D and the engaging piece Dconsists of a spring or piece of resilient material suitably connectedwith said armature.

I have described in detail a particular construction embodying myinvention; but it is of course evident that various constructions may beused without departing from the spirit of my invention, and I thereforedo not wish to be limited in any manner by the construction shown.

The use and operation of my invention are as follows: In the operationof electric motors, for example, it is customary to start the motor withan external resistance in the armature-circuit and then vary saidresistance in the manner desired. When a device such as hereinillustrated is used in connection with motors, it insures the return ofthe arm controlling this resistance to its initial point as soon as thecircuit through the field-magnets of the motor is brokenor falls below apredetermined amount, thus preventing injury to the motor due to excessof current through the armature. If when mydevice is used the circuitthrough the motor is completed, the magnet 'D attracts its armature D,said armature being moved into contact with the pole-pieces of themagnet. The arm A is now moved past the contacts B, so as to vary theresistance in the arimtture-circuit of the motor, the engaging piece Dengaging one of the notches A when the arm A is released and holdingsaid arm either in one of its in termediate positions or in its closedposition on the contact B It, for example, the engaging piece D wererigid and fixed with 'relation to the armature D, it will be seen thatsaid armature would be moved out of contact with the pole-pieces of themagnet D each time the engaging piece moved from one notch to another.Since the attractive force of the magnet is at a maximum and is muchgreater when the armature is in contact with the pole-pieces, it will beseen that under such conditions a much stronger magnet will be necessaryto move this armature backin contact with the pole-pieces than isnecessary to do the work of holding it in contact therewith. By makingthe engaging piece D of resilient material it springs in and outas thearm A is moved, so as to engage the various notches A without moving thearmature D away from the pole-pieces of the magnet, and hence insuresthe proper working of the de vice under all conditions. It will also beseen that this construction by z'tllowing the armature D to be always incontact with the polepieoes of the magnet makesit possible to use a muchsmaller magnet and at the same time obtain better results.

By the construction herein shown, whereby the controlling-arm can bemoved without displacing the armature or moving it from contact with thepole-pieces of the magnet, I am enabled to use my device in connectionwith a series-wound motor. If the armature moved away from thepole-pieces when the controlling'arm is moved, the device could not becommercially used with a series-wound motor because of the counterelect-romotive force upon the action of the magnet.

I claim 1. An electric switch, comprisinga movable arm, a retractingdevice for said arm, an elastic engaging device for engaging said armand holding it in a predetermined position, an electromagnet forcontrolling said engaging device, said engaging device free at one endand fastened at the other end to the armaceases ture of saidclectromagnet so as to be free to move with relation thereto.

2. An electric switch, comprisinga movable arm provided with aretracting device, an electromagnet associated with said arm, anarmature movably mounted in proximity to the poles of said electromagnetand adapted to be attracted thereby, a spring part connected with saidarmature and provided with an engaging end adapted to engage said armand hold it in a predetermined position while said armature is attractedby the pole-pieces of said magnet.

3. An electric switch, comprisinga movable arm provided with aretracting device, a spring engaging piece associated with said arm andhaving an engaging end adapted to engage it and hold it in apredetermined position, an electromagnet associated with said engagingpiece and provided with an armature to which said engaging piece isconnected, said armature movably mounted in proximity to the pole-piecesof the magnet and controlling the position of said spring engaging pieceso as to bring it into engagement wit-l1 the arm when the electromagnetis energized.

at. he combination with an electric motor of a magnet contained in thecircuit of said motor, a movable arm adapted to control the circuitthrough the armature of said motor, said arm provided with a suitableretracting device, a spring engaging piece provided with a projectingpart adapted to engage said arm while it is being moved in controllii'igthe circuit and hold it in a predetermined position, said springengaging piece connected with the armature of said magnet, the parts soarranged that the arm can be moved to its predetermined position withoutmoving the ar- -mature of said magnet from contact with its opposedpole-pieces.

5. An electric switch, comprisinga movable arm provided with aretracting device, an clectromagnet associated with said arm, anarmature movably mounted in proximity to the poles of said magnet andadapted to be attracted thereby, a spring engaging piece connected withsaid armature, a series of notches associated with said arm adapted tobe engaged by said engaging piece, the parts so arranged that said armcan be moved so that the engaging piece moves from notch to notchwithout removing the armature from contact with the pole-pieces of themagnet.

THOMAS G. MEINEt IA.

Witnesses:

DONALD M. CARTER, HOMER L. KRAFT.

